Scientists may have discovered ninth planet on far reaches of solar system

AN INVISIBLE giant is lurking on the edge of our solar system: Scientists are hailing the possible discovery of a new planet — 10 times the size of Earth.

Jamie Seidel, AFP

News Corp Australia NetworkJanuary 21, 20169:34am

Evidence of a Ninth Planet2:58

Caltech's Konstantin Batygin, an assistant professor of planetary science, and Mike Brown, the Richard and Barbara Rosenberg Professor of Planetary Astronomy, discuss new research that provides evidence of a giant planet tracing a bizarre, highly elongated orbit in the outer solar system. Courtesy: YouTube/caltech.

January 21st 2016

2 years ago

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AN INVISIBLE giant is lurking on the edge of our solar system. Scientists are hailing the possible discovery of a new planet 10 times the size of Earth.

The object follows a “bizarre, highly elongated orbit in the distant solar system,” taking it — on average — some 20 times further from the Sun as Neptune, say researchers at the California Institute of Technology (Caltech).

Researchers Konstantin Batygin and Mike Brown say they found the planet through mathematical modelling and computer simulations, and have not yet observed the object directly.

But they are convinced it is there.

“For the first time in over 150 years, there is solid evidence that the solar system’s planetary census is incomplete.”

Speculation of another world, variously named ‘Planet X’ or ‘Nemesis’ among others, has been circulating for almost a century.

“This would be a real ninth planet,” said Brown, a professor of planetary astronomy.

“There have only been two true planets discovered since ancient times, and this would be a third,” the researchers said in a statement. “It’s a pretty substantial chunk of our solar system that’s still out there to be found, which is pretty exciting.”

There are currently eight celestial bodies recognised as planets in our solar system. There used to be nine but Pluto was demoted to the status of Dwarf Planet in 2006.

Edge of solar system ... This artistic rendering shows the distant view from Planet Nine back towards the sun. Picture: R. Hurt/APSource:AP

PLANET, OR CELESTIAL BODY?

The mathematically inferred body sits in an orbit between the outer edge of our solar system and the Kuiper Belt. This icy cloud debris left over from the formation of the sun and inner planets billions of years ago is the source of comets.

So would Planet Nine be a world, or a large chunk of ice?

Professor Brown states that as it is likely to be some 5000 times heavier than Pluto, there should be no debate over its planetary status.

It also casts its gravitational influence over a larger region of the solar system than any other: This makes it “the most planet-y of the planets in the whole solar system,” he says.

Professor Brown should know: He earned notoriety as one of the main advocates for stripping Pluto of its status as a planet.

So why haven’t we actually seen it?

It’s a long, long way out.

“In fact, it would take this new planet between 10,000 and 20,000 years to make just one full orbit around the Sun.”

Distant relatives ... This is an artist's concept of Kuiper Belt object 2003 UB313 (nicknamed Xena) and its satellite Gabrielle. The unusual orbits of the solar system’s most distant celestial bodies points directly towards the existence of a ninth planet.Source:Supplied

WHERE DID IT COME FROM?

The most common planet discovered so far in our galaxy does not exist in our solar system:

Super Earths.

“One of the most startling discoveries about other planetary systems has been that the most common type of planet out there has a mass between that of Earth and that of Neptune,” says Batygin. “Until now, we’ve thought that the solar system was lacking in this most common type of planet. Maybe we’re more normal after all.”

Super-earths are most common planet known to humanity right now, but none in SolSys... Unless... Planet 9? pic.twitter.com/M3Si6qk2KA

Astrophysicists believe the dominant influencers of the early formation of our solar system were what are now the cores of Jupiter, Saturn, Uranus and Nepune. These large bodies ‘stole’ all the gas around them — including from smaller worlds like Earth and Mars.

“But there is no reason that there could not have been five cores, rather than four,” says Brown.

It’s known the gas giants ‘jostled’ each other into their current positions.

A fifth could have been ejected from the inner solar system on an unusual orbit if it stumbled too close to Jupiter or Saturn.

Many of the most distant known objects in the solar system — with orbits taking them beyond Neptune — are all mysteriously arrayed on one side of the orbital plane. Only a planet 10 times the size of Earth, in roughly the orbit indicated (in orange) could produce this effect. Source: CaltechSource:Supplied

OUTLIERS EXPLAINED

The strongest evidence for the existence of Planet Nine is the mysterious behaviour of the ‘iceblock belt’, the Kuiper Belt, beyond Neptune.

“Although we were initially quite sceptical that this planet could exist, as we continued to investigate its orbit and what it would mean for the outer solar system, we become increasingly convinced that it is out there,” says assistant professor of planetary science Konstantin Batygin.

In 2014 researchers Chad Trujillo, and his colleague Scott Sheppard published a study that revealed 13 of the known most distant objects orbiting our Sun shared similar, obscure orbits.

They suggested the possibility of one — or perhaps two — small planets could have caused these objects to be ‘bent’ out of their usual orbits.

“It’s almost like having six hands on a clock all moving at different rates, and when you happen to look up, they’re all in exactly the same place,” Professor Brown says.

This degree of ‘herding’ required much more than a small planet. — or even the combined pull of the comets in the Kuper Belt itself.

After that, it was a process of mathematical elimination to establish the ‘clockwork’ necessary to put those six ‘dials’ in place.

The above chart shows how large a plant would have to be in order to clear its orbital zone. Source: Caltech / Astronomical JournalSource:Supplied

ORBITAL GEOMETRY

After running a series of computer orbit simulations, one in particular stood out.

A massive planet in an unorthodox orbit — one which sees it swing around the Sun angled some 180 degrees off the plane of all the other planets in our solar system — could explain the observed ‘herding’ of Kupier Belt objects.

Further study demonstrated such orbits could be stable, without causing these distant objects to tumble into each other.

Its presence would also explain the odd orbit of dwarf planet Sedna. Discovered in 2003, its orbit never takes it close enough to Neptune for it to have been bumped so far out of alignment.

So where is Planet Nine and how bright is it? I finally have enough time to post. https://t.co/0w67OorQiX HINT: it is not super faint!

“Planet Nine in its proposed orbit naturally produces Sedna-like objects by taking a standard Kuiper Belt object and slowly pulling it away into an orbit less connected to Neptune,” the researchers wrote.

Planet Nine’s pull also explain the oddly perpendicular orbit of many other Kuiper Belt bodies.

“We plotted up the positions of those objects and their orbits, and they matched the simulations exactly,” says Brown. “When we found that, my jaw sort of hit the floor.”

But, despite the mountain of evidence, the faint glow of Planet Nine has not yet been seen in the heavens.

“I would love to find it,” says Brown. “But I’d also be perfectly happy if someone else found it ... We hope that other people are going to get inspired and start searching.”